Process of preparing phosphoric acid esters of hydroxyalkyl isoalloxazines



Patented Mar.15,1938 2,111,491 UNITED STATES PATENT OFFICE PROCESS OF PREPARING PHOSPHORIC ACID ESTERS OF HYDROXYALKYL ISO- ALLOXAZINES Richard Kuhn and Herman Rudy, Heidelberg, Germany, assignors to Winthrop Chemical isoalloxazines (flavines) show a growth promotbe carried out by means of organic acylating 5 ing action which is similar to the physiological agents, such as acetic acid anhydride or by aceactivity of vitamin B2 (compare our copending talization, for instance, with acetone. The aqueapplication Serial No. 29,732, filed July 3, 1935) ous solutions of the ethers or esters thus obtained In accordance with the present invention derivare then extracted by means of a suitable organic l0 atives of the said 9-poly-hydroxya1kyl-isoalloxasolvent, such as a halogenated hydrocarbon, for zines of biological interest are obtainable by instance, chloroform or carbon hloride, or reacting upon the 9-poly-hydroxyalkyl-isoalloxaby means .of alcohols, particularly her mem zines with a phosphorus compound selected from bered alcohols, such as butyl and amyl alcohol, the group consisting of phosphorus halides, phosor by means of organic esters, such as acetic l5 phorus oxyhalides, phosphorus oxides and metaester. By an extraction process of the it kind l5 phosphoric acid esters. Phosphoric acid esters the ester or acetal compound of the starting are thus obtainable which are considered to have material is dissolved by the extracting agent, the following general formula: whereas the phosphoric acid ester compound relet-crown us in the aqueous solution. By careful treati, N ment with a dilute acid or alkali lye, the hydroxyl 20 7 8 1k groups may then be set free without splitting oil? A the horic acid radical. 6 5 t phosphoric acid esters of the 9-poly-" hydromalnl-isoalloxamnes, particularly those of Q-poly-hydroxyamylfifl-dimethyl-isoalloxazines, 25

wherein A stands for an aromatic ring system, for instance, the phosphoric acid ester of 9-(dpreferably of the benzene series and It stands for ribltyl) -6.'7-dimethyl-isoalloxazine, form proda hydroxyalkyl group. ucts with albuminous substances which exert a In accordance with the present invention the catalytic action on oxidation processes. Thus,

manufacture of the said phosphoric acid esters of for instance, a catalytic action on the oxidation 30 9-poly-hydroxyalkyl-isoalloxazines (fiavines) is of hexose-mono-phosphoric acid may be detected. performed by reacting upon a, 9-hydroxyalkyl Furthermore, the phosphoric acid esters, similar isoalloxazine with a phosphorus halide or oxyto the 9-polyhydroxyalkyl-isoalloxazines themhalide, or with a phosphorus oxide or meta-phosselves, exert a growth promoting action.

phoric acid ester. Phosphorus oxychloride is The invention is further illustrated by the fol- 35 preferably used as the esterifying agent. The lowing examples without being restricted reaction is advantageously carried out in the thereto:-

presence of an organic base, such as pyridine, Example 1.,-2.68 parts by weight of phosphorquinoline, triethylamine and the like. Instead of us oxychloride are added to the ice cooled soluthe 9-poly-hydroxyalkyl-isoalloxazines also derivtion of 6.5 parts by weight of 6.7-dimethyl-9-(d- 40 atives thereof containing at least one free hy- -ribltyl)-lsoalloxazlne in 3500 parts by weight of droxyl group, such as the acetals, particularly pyridine. The mixture is left standing for one their acetone compounds, may be employed. The ,hour at 0 C. and for further 8 hours at room reaction is best started at low temperature and temperature in the dark and then treated with further carried out while gently heating. The ice and sodium acetate. After the pyridine has 45 phosphorus compounds may be used in excess. evaporated in vacuo, the crude product is taken The esters thus obtainable may be further up in 3000 parts by weight of water and treated purified bymeans of their difiicultly soluble metal with aqueous silver nitrate. After cooling to 0 salts, for instance, by means of their lead, copper, C. a red silver salt separates in flakes. It is disbarium, calcium salts and preferably by means of solved in 20% acetic acid while adding sodium 50 their red silver salts from which the acid phosacetate while warm and is decomposed while inphoric acid esters are liberated in the usual man-, troducing hydrogen sulfide. The mixture is filner, for instance by means of hydrogen sulfide. tered and the solution which is free from silver In the form of their alkali metal salts the ester is concentrated and treated with an excess of compounds are well crystallized compounds alcohol. On standing in the refrigerator, the 55 which dissolve in water. In the electric field mono-sodium salt of the 6.7-dimethyl-9-(d-ribthey migrate to the anode, contrary to the 9- ity1)-isoalloxazine phosphoric acid crystallizes in poly-hydroxyalkyl-isoalloxazines themselves. If a. good yield. According to analysis the product unchanged starting material is present in the recorresponds to the formula: CmH19N4Os-OPO3H2.

0 action product the latter may be separated there- Company, of New York Inc., New York, N. Y., a. corporation No Drawing. Application January -24, 1936, Se-

rial No. 60,742.

12 Claims.

This invention relates to a process of preparing phosphoric acid esters of poly-hydroxyalkyllsoalloxazines.

Poly-hydroxyalkyl substitution products of In Germany January 26, 1935 (Cl. 260-29) e from by esterifying or etherlfying the hydroxyl groups of the poly-hydroxyalkyl-isoalloxazine and the still free hydroxyl groups of the reaction product. The esterification or etheriflcation may Example 2.--5 parts by weight of 9-dihydroxypropyl-fiavine (Q-dihydroxypropyl-lsoalloxazine) melting at 300 C. are dissolved in 10,000 parts by weight of pyridine while hot, and, after cooling with ice, treated with an ice cooled solution of 2.67 parts by weight of freshly distilled phosphorus oxychloride in 100 parts by weight of pyridine. After standing for 20 hours at room temperature in the dark, the mixture is treated with a small quantity of sodium acetate while adding ice, evaporated to dryness in vacuo and redistilled twice with a small quantity of water in order to remove the pyridine. The residue is dissolved in 30,000 parts by weight of water while hot, and the silver salt of the fiavine phosphoric acid is precipitated by means of silver nitrate at weakly ammoniacal reaction. The fiocc'ulent precipitate is washed with water, taken up in hot acetic acid and decomposed with hydrogen sulfide after the addition of sodium acetate. The silver sulfide precipitate is washed with warm water. The solution which has been centrifuged oil! is evaporated to dryness together with the washing water, the residue is dissolved in hot water, filtered and treated with the same volume of alcohol while hot. The sodium salt of 9-dihydroxypropyl-fiavine phosphoric acid crystallizes in thin needles which combine to ball-like aggregates. In the electric field (pH 7.2; 220 volts, 15, milliamperes) it migrates to the anode.

In an analogous manner the phosphoric acid esters of 6.7-dimethyl-9-dihydroxypropyl-flavine and of 9-(l-arabityl) and Q-(d-arabityl) -flavine and of the corresponding 6.7-dimethyl compounds are obtained when starting with the corresponding fiavine compounds.

Example 3.3.45 parts by weight o1 6.7-dimethyl-Q-(d-ribityl)-isoalloxazine are dissolved in 4000 parts by weight of dry pyridine while hot. A mixture of 17.5. parts by weight of phosphorus oxychloride with 200 parts by weight of pyridine is added to the solution which has been cooled to 2530 C. After 12 hours standing at room temperature the mixture is occasionally heated to 40-50 C. while subsequently adding further phosphorus oxychloride (5 parts by weight in 50 parts by weight of pyridine). For completing the phosphorylation the mixture is repeatedly heated within the next 24 hours to 50 C. eventually while adding further phosphorus oxychloride. It is then heated with 10 parts by weight of acetic anhydride for a quarter of an hour to 70-80 0., about 5000 parts by weight of ice are added and the nomphosphor'ylated flavine extracted as tetra-acetyl compound by means of chloroform (three times with one third of the total volume).

I The aqueous layer is acidified with glacial acetic acid. 1 part by volume of the concentrate is left standing in the refrigerator with one third part by volume of molar calcium acetate solution and 1 part by volume of ethyl alcohol, whereby the calcium salt of the 6.7-dimethyl-9-(d-ribityl) isoalloxazine is obtained in yellow flakes.

Example 4.l part by weight of 9-dihydroxypropyl-isoalloxazine is dissolved in 2000 parts by weight of dry pyridine while hot and, after. cooling to 25 C., treated with 10 parts by weight of phosphorus oxychloride in 200 parts by weight of pyridine. The further working up proceeds as in Example 3. The properties of the product thus obtained correspond to the properties of the product obtained according to Example 2.

We claim:

1. The process which comprises reacting upon a compound selected from the group consisting of 9-polyhydroxyalkyl-lsoalloxazines and derivatives thereof containing at least one free hydroxyl group with a phosphorus compound selected from the group consisting of phosphorus halides, phosphorus oxyhalides, phosphorus oxides and metaphosphoric acid esters.

2. The process which comprises reacting upon a compound selected from the group consisting of 9-polyhydroxyalkyl-isoalloxazines and derivatives thereof containing at least one free hydroxyl group with a phosphorus compound selected from the group consisting of phosphorus halides, phosphorus oxyhalides, phosphorus oxides and metaphosphoric acid esters in the presence of an organic base.

3. The process which comprises reacting upon a compound selected from the group consisting of 9-polyhydroxyalkyl-isoalloxazines and derivatives thereof containing at least one free h'ydroxyl group with phosphorus oxychloride in the presence of an organic base.

4. The process which comprises reacting upon a compound selected from the group consisting of 9-polyhydroxyalkyl-isoalloxazines and derivatives thereof containing at least one free hydroxyl group with phosphorus oxychloride in the presence of an organic base while gently heating.

5. The process which comprises reacting upon a 9-tetrahydroxyamyl-isoalloxazine with phosphorus oxychloride in the presence of an organic base while gently heating.

6. The process which comprises reacting upon a 9-pclyhydroxyalkyl-isoalloxazine with phosphorus oxychloride in the presence of pyridine.

'7. The process which comprises reacting upon a 9-polyhydroxyalykl-isoalloxazine with phosphorus oxychloride in the presence of pyridine while gently heating.

8. The process which comprises reacting upon a 9-tetrahydroxyamyl-isoalloxazine with phosphorus oxychloride in the presence of pyridine while gently heating.

9. The process which comprises reacting upon a 6.7-dimethyl-9-tetrahydroxyamyl-isoalloxazine with a phosphorus compound selected from the group consisting of phosphorus halides, phosphorus oxyhalides, phosphorus oxides and meta- RICHARD KUHN.

HERMANN RUDY. 

